Original Article

KW Chau, DKK Ng, CKL Kwok, PY Chow, JCS Ho
Correspondence: D K K Ng, dkkng@ha.org.hk

ABSTRACT
Objective To identify the clinical factor(s) that identify obstructive sleep apnoea syndrome (OSAS) in children.
Methods A prospective study of children referred to the sleep clinic of the paediatric department was conducted in a public non-teaching regional hospital in Hong Kong. A standard questionnaire was administered and overnight sleep polysomnography was performed in a consecutive series of patients. Logistic regression analysis was performed to obtain significant risk factors for prediction of OSAS in this series of patients.
Results Sixty-two children were enrolled into the study and 22 were diagnosed to have OSAS. Logistic regression analysis showed that, among all the answers, 'snoring every night' is the single most significant risk factor (p<0.0001) to predict OSAS. 'Snoring every night' has a sensitivity of 91% and specificity of 75% for OSAS patients. It also has a positive predictive value of 67% and negative predictive value of 94%.
Conclusion Snoring every night is an important risk factor in identifying OSAS in children. Priority for an overnight sleep polysomnogram should be given to those with this symptom.

Keywords: children, obstructive sleep apnoea, OSAS, risk factors, questionnaire
Singapore Med J 2003; 44(11): 570-573

VYT Lim, CNS Chan, V Kwok, KH Mak, TH Koh
Correspondence: A/Prof Charles Chan, Charles_CHAN@nhc.com.sg

ABSTRACT
Coronary angiography and angioplasty are usually performed via transfemoral access. Though this route provides an easier vascular access, it is associated with a small but potentially serious incidence of vascular complications at the puncture site that may result in significant groin haematoma, blood transfusion or require surgical repair. A useful alternative approach is through the transradial access. This route has a very low rate of vascular complications and also allows early mobilisation of patients. We performed an analysis of our experience with transradial angiography and angioplasty, demonstrating this to be a safe and effective technique suitable for most patients.

Keywords: Allen’s test, coronary angiography, coronary angioplasty, transradial angiography, transradial intervention
Singapore Med J 2003; 44(11): 563-569

KY Yang, MC Wang, SJ Yeo, NN Lo
Correspondence: Yang Kuang Ying, kyyang@orthopods.net

ABSTRACT
Fifty consecutive patients with isolated medial compartmental osteoarthritis of the knee were treated with minimally invasive unicompartmental knee arthroplasty (UKA). An equal number of patients with total knee arthroplasty (TKA) performed in the same period were selected and matched with respect to age, pre-operative range of motion and radiological grade of knee arthrosis. Both groups of patients were prospectively followed up. Comparison of the two groups at six months show that patients with minimally invasive UKA have less blood loss, quicker rehabilitation, earlier ambulation, shorter hospitalisation stay and better post-operative range-of-motion with reduced hospitalisation cost. Reflecting on a six-month follow-up and immediate post-operative events, we conclude that minimally invasive UKA is a relatively more cost effective procedure than TKA for these patients.

Keywords: unicompartmental knee arthroplasty minimally invasive
Singapore Med J 2003; 44(11) :559-562

MP Chlebicki, EK Teo
Correspondence: M P Chlebicki, pchlebicki@hotmail.com

ABSTRACT
Peripherally inserted central catheters are frequently used whenever reliable central venous access is required for a prolonged period of time. The objective of this study was to review utilisation profile, complication rates and outcomes of patients who were treated in our hospital with the therapy that required placement of the peripherally inserted central catheter. We reviewed the medical records of all patients who had peripherally inserted central catheter placed between the beginning of July and the end of October 2002. Five patients who remained hospitalised at the time of review (six weeks after the last day of study period) were excluded. Seventy-eight patients with 94 peripherally inserted central catheters were analysed in detail. Sixty-four peripherally inserted central catheters (68.1%) were placed for prolonged antibiotic therapy, 27 (28.7%) mainly to administer total parenteral nutrition and 3 (3.2%) were inserted for other reasons. Catheters were in place before removal for a mean 17.2 days. Forty-eight catheters (51.1%) were removed after completion of therapy on average 20.2 days after insertion. Complications were frequent but minor. Thirty-three catheters (35.1%) were removed due to catheter-related complications. The most common complication were phlebitis followed by accidental removal. In summary, peripherally inserted central catheters proved to be reasonably safe and a reliable way of providing therapy requiring prolonged intravenous access. Complications were frequent but relatively minor. Complication rates in our study were similar to those reported in other studies on this subject. Peripherally inserted central catheters remain a convenient and reasonable alternative to other centrally or peripherally inserted venous devices.

Keywords: peripherally inserted central catheter, catheter-related infection, central venous catheterisation
Singapore Med J 2003; 44(10): 531-535

CCT Lim, TPL Roberts, YY Sitoh, F Hui
Correspondence: C C T Lim, tchoyoson_lim@ttsh.com.sg

ABSTRACT
Objective Dynamic perfusion magnetic resonance (MR) techniques may be used to track the susceptibility effects of gadolinium contrast material as it passes through the brain. We describe three intracranial tumours that showed progressively rising signal intensity above the baseline during first-pass contrast-enhanced echo-planar imaging (EPI) MR imaging.
Methods Multiphase acquisition using single-shot EPI was performed during rapid bolus contrast injection. Ten studies, using either spin-echo or gradient-echo EPI sequences, were carried out in eight patients with intracranial tumours. Time-signal intensity graphs and regional cerebral blood volume (rCBV) were reviewed.
Results In seven studies, the signal intensity within the tumour showed initial signal drop and quick recovery to baseline and increased rCBV. Three studies revealed progressively rising signal intensity. These patients were all imaged using a spin-echo EPI method and subsequent histology revealed meningioma, hemangiopericytoma and pinealblastoma.
Conclusion Dynamic perfusion MR methods may be used to study intracranial tumours. However, in short relaxation time spin-echo EPI, the T1- effect of gadolinium becomes noticeable during the first-pass acquisition in extra-axial tumours that lack a well-developed blood-brain barrier. Careful selection of patients and pulse sequence is essential to avoid this potential pitfall.

Keywords: magnetic resonance imaging, echo-planar imaging, brain neoplasms, perfusion, hemangiopericytoma
Singapore Med J 2003; 44(10): 526-530

WM Yue, BK Tay, ST Kasinathan
Correspondence: W M Yue, yuewm@singnet.com.sg

ABSTRACT
Donor site morbidity, which occurs in 15% to 20% with the use of autografts for anterior cervical fusion, is eliminated with the use of allografts. While allografts from the iliac crest, ribs, fibula, femoral head and skull have been used in anterior cervical fusion, the use of patellar allografts has not been previously reported. Twenty-two patients underwent Cloward anterior cervical decompression and fusion using bicortical patellar allografts from 1993 to 1997. Fifteen patients, with a follow-up period of at least two years, were reviewed. Eleven patients (73.4%) had good or excellent results at an average of 42.8 months after surgery. Fourteen patients (93.4%) achieved union. Two patients (13.3%) developed collapse of the graft with extrusion, one of whom still achieved union. These results are comparable to those reported of anterior cervical fusion using autografts or other types of allografts.

Keywords: allograft, Cloward, anterior cervical fusion, patella
Singapore Med J 2003; 44(10): 521-525

Hany Ariffin, SP Chen, H-L Wong, A Yeoh
Correspondence: Dr Hany Ariffin, hany@um.edu.my

ABSTRACT
In childhood acute lymphoblastic leukaemia (ALL), cytogenetics play an important role in diagnosis, allocation of treatment and prognosis. Conventional cytogenetic analysis, involving mainly karyotyping in our experience, has not been successful in a large proportion of cases due to inadequate metaphase spreads and poor chromosome morphology. Our aim is to develop a highly sensitive and specific method to screen simultaneously for the four most frequent fusion transcripts resulting from specific chromosomal translocations, namely, both the CML- and ALLtype BCR-ABL transcripts of t(9;22), E2A-PBX1 transcript of t(1;19), the MLL-AF4 transcript of t(4;11) and TEL-AML1 (also termed ETV6-CBFA2) of the cryptic t(12;21). A multiplex reverse transcription polymerase chain reaction protocol (RT-PCR) was developed and tested out on archival bone marrow samples and leukaemia cell lines. In all samples with a known translocation detected by cytogenetic techniques, the same translocation was identified by the multiplex-PCR assay. Multiplex RT-PCR assay is an effective, sensitive, accurate and cost-effective diagnostic tool which can improve our ability to accurately and rapidly risk-stratify patients with childhood ALL.

Keywords: risk-stratification, multiplex, RT-PCR, acute lymphoblastic leukaemia
Singapore Med J 2003; 44(10): 517-520

O Ghazali, KB Chua, KP Ng, et al
Correspondence: Chua Kaw Bing, chuakawbing@yahoo.com.sg

ABSTRACT
This paper reports a second outbreak of acute haemorrhagic conjunctivitis due to coxsackievirus A24 in peninsular Malaysia. Between June 2002 and early October 2003, 10,327 patients, comprising 3,261 children and 7,066 adults, were treated for acute conjunctivitis in 11 government health clinics in the Melaka Tengah district of the state of Melaka. The figure grossly underestimates the size of the outbreak; as no patients treated in private clinics in the same district were included. Institution and household surveillance showed that the commonest presenting clinical feature of the illness was eye-discharge (91.2%), followed by foreign body sensation (81.8%), pain (78.3%) and subconjunctival haemorrhage (74.4%). The mean duration of illness was 6.5 and five days for patients with and without subconjunctival haemorrhage respectively.

Keywords: epidemic, conjunctivitis, coxsackievirus A24
Singapore Med J 2003; 44(10): 511-516

W Luman, KL Ng
Correspondence: Dr Widjaja Luman, gm2wid@sgh.com.sg

ABSTRACT
Background Patients with iron deficiency anaemia (IDA) are commonly referred to the gastroenterologists for exclusion of gastrointestinal (GI) pathologies. The British Society of Gastroenterology (BSG) has published a guideline for management of IDA. As recommended by this guideline, all patients should have examinations of both upper and lower GI tract with the exception of pre-menopausal women younger than 45 years old. The primary aim of this audit was to determine how thoroughly patients referred to our unit at the Singapore General Hospital had been investigated. The secondary aim was to determine the yield rate of gastroscopy and lower gastrointestinal investigations (colonoscopy or barium enema) in our patients.
Methods We reviewed the case notes of patients who underwent gastroscopy for indication of anaemia between the period from April to December 1999. We classified iron deficiency anaemia as having haemoglobin of lower than reference range with either low ferritin level or iron/ TIBC ratio of less than 10%.
Results Of a total of 326 patients reviewed, 172 patients (65 men, 109 women) met the inclusion criteria of IDA. The median age for the group was 59 (Range 16 to 88) years old and there were 107 (62.2%) women. There were 31 female patients younger than 45 years old (group A) and 141 patients in group B which included all the males and females older than 45 years old. Due to the method of data retrieval, all of the patients in group A fulfilled the standard set by the BSG guideline in that they all underwent gastroscopy. In this group, few gastrointestinal pathologies were found (one patient with peptic ulcer and two patients with colonic cancer). In terms of finding potential gastrointestinal causes of IDA, the yield rate of gastroscopy and colonoscopy were 3.2% and 13.6% respectively. In group B, 96 patients (68%) underwent upper and lower gastrointestinal investigations. Evaluation with gastroscopy showed peptic ulcer disease in 31 patients (21.7%) and gastric cancer in 9 patients (6.3%). Only 96 patients (68.1%) in group B had lower gastrointestinal investigations. Twenty-six patients were found to have gastrointestinal disorders (12 patients with colon cancer, 10 colonic polyps, one Crohn's disease, one colonic tuberculosis and two haemorrhoids). The yield rate of gastroscopy and colonoscopy were 31.2% and 25% respectively.
Conclusion In this study of patients with confirmed IDA, we found much higher incidence of gastrointestinal disorders in the group of male and postmenopausal women than in the group with premenopausal women. Furthermore, over 30% of patients in this group did not undergo lower gastrointestinal tract investigations as recommended by the BSG guideline. We also found two cases of colonic cancer in the latter group. We would recommend bidirectional endoscopy for postmenopausal women and men with IDA. For premenopausal women, we would recommend similar approach unless there are clinical pointers to dietary iron deficiency or menorrhagia.

Keywords: iron deficiency anaemia, gastroscopy, colonoscopy
Singapore Med J 2003; 44(10): 504-510

AT Sia, WR Camann, CE Ocampo, RW Goy, HM Tan, S Rajammal
Correspondence: Dr A T Sia, athsia@kkh.com.sg

ABSTRACT
Aim Apart from conventional epidural analgesia (EA), the combined spinal-epidural (CSE) modality is fast becoming a popular technique for treating labour pain. In this study, we investigated the differences in the patient profile and outcome between CSE and EA for labour pain in KK Women's and Children's Hospital.
Methodology Data pertaining to 1,532 healthy parturients who had received either CSE or EA for labour pain during a six-month period was systematically collected by using a specially designed form. Multiple logistic regression analysis was used to determine the independent predictors of patient satisfaction and the relation of parturient factors on the choice of block. The side effects and the outcome of labour were also compared.
Results CSE accounted for 80% of all neuraxial blocks performed for labour analgesia (vs 20% for EA). Anaesthesiologists were more inclined to using CSE than EA for multiparous parturients (OR 2.03, p<0.01) in a more painful (OR=1.61, p=0.03) and advanced stage of labour (OR=1.12, p=0.03). The need for supplemental analgesics was greater for EA (p<0.01). Patient satisfaction was higher for CSE (OR=1.77, p<0.026). CSE had a higher risk of pruritus (29% vs 14%, p<0.01) but lower risk of post block neural deficits (0% vs 2%, p<0.01) than EA. No difference in the mode of delivery was detected between the two groups.
Conclusion CSE is a safe and good alternative to EA as a technique of neuraxial block for labour analgesia.

Keywords: combined spinal epidural, epidural, analgesia, labour
Singapore Med J 2003; 44(9): 464-470